Seismic technology, particularly 3-D seismic, has revolutionized the oil and gas industry in the past 30 years. New techniques like wide-azimuth acquisition and reverse time migration continually push the envelope in the quest for better resolution.

But even the best seismic dataset has its limitations. Very small targets remain difficult to image, and interpreters can only take a stab at identifying lithologies.

Adrok Group has developed a different type of imaging tool. It uses coherent radio waves and a microwave imaging spectrometer to peer beneath the surface. Atomic dielectric resonance (ADR) technology has been developed to overcome the limitations of synthetic aperture radar (SAR) and ground penetrating radar (GPR), and it’s being used in oil and gas and in mining operations to determine rock types deep in the ground.

“We were really frustrated with the lack of penetration of GPR devices,” said Gordon Stove, managing director of Adrok. “So we took the system apart and figured out how to get deeper penetration using radio waves.” Stove’s father, Dr. Colin Stove, had worked with SAR sensors both from satellites and from the space shuttle experiment in the early 1980s and was aware of their ground-penetrating capabilities. He developed a tool that uses directional electromagnetic radiation as resonating transmitting and receiving beams of energy rather than the omnidirectional electromagnetic signals typical of conventional GPR systems.

The results have been impressive – Gordon Stove said the ADR system can penetrate as deep as 4 km (2.4 miles). But there’s even more to the story.

“Although one of our selling points is the fact that we can send a radio wave deep into the ground, we thought the missing ingredient in other geophysical tools in the marketplace is that they don’t actually classify the rock type,” he said. “They just produce an image of the subsurface, and interpreters try to guesstimate what they’re looking at.”

Adrok researchers turned to spectroscopy, commonly used in forensic science, to apply to the returning radio signal. Over time the company has built a library of different rock types to classify the signals coming from the field.

Another advantage over seismic is that the system is nondestructive. This enables it to be deployed in places where a seismic survey might be unrealistic. It can be deployed from the back of a truck or even by a person walking along the ground.

Stove said it took most of a decade to develop the technology, partly because Adrok is a private company with a limited staff and had to fund the R&D itself. It launched the commercial product in the spring of 2007 and since then has performed more than 100 surveys for oil and mining companies, one leading to a major gas discovery in Morocco.

“We tend to operate in the niche markets where seismic, which is the dominant player with 98% of the market, can’t operate,” Stove said. “Trying to define a coalseam for a coalseam gas play that is 1 m to 5 m (3 ft to 16 ft) in depth is quite challenging for seismic. That’s where we fit in.” The procedure, though currently only used onshore, also works well with igneous rock, basalt, and salt, he said.

Adrok is primarily active in Canada, the US, and Australia, and Stove hopes to increase its US activities by becoming involved in shale plays. “We’re very keen to help the US market,” he said.

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